A conventional walker as shown in FIGS. 1 and 2 includes a front frame 4 having two pin holes 41, two side frame units 5 and two locking units 6. Each of the side frame units 5 includes a side frame body 51 and an adaptor 52 sleeved on the side frame body 51. Each of the locking units 6 includes a lock releasing lever 61 mounted on the adaptor 52, a locking pin 62 extending through the adaptor 52, connected to the lock releasing lever 61 and movably inserted into the respective pin hole 41 to lock the side frame body 51 relative to the front frame 4, and a spring 63 connected to the adaptor 52 and the locking pin 62. An upwardly pulling action to the lock releasing lever 61 results in upward movement and removal of the locking pin 62 from the respective pin hole 41 so as to permit turning of the side frame body 51 relative to the front frame 4 in folded and unfolded positions.
Such a walker is generally used to assist ambulation and provide additional stability for people who are elderly, infirm, have a disability, or are in rehabilitation, and who cannot sufficiently apply an upward pulling action to the lever 61 for releasing the locking pin.